This invention relates generally to the field of surgical methods and apparatus for anchoring a suture to a bone mass, so that the suture can be used to secure a ligament or other tissue to the bone mass.
More specifically, the present invention relates to a method and apparatus for threading a suture through a suture anchor after the suture anchor has been driven into a bone mass.
In numerous surgical procedures, an object is either directly attached to a bone, or is indirectly attached to the bone with a suture. In the former case, a ligament or a prosthesis may be directly attached to the bone. In the latter case, bodily tissue may be supported by sutures that are anchored in the bone, thereby using the bone as a structural support. An example of this latter type of procedure is the percutaneous bladder neck suspension, in which sutures anchored in the pelvis are attached to tissue adjacent to the urethra to support and thereby suspend the bladder neck.
Various types of suture anchors have been devised to anchor the suture to the bone, as exemplified by the following U.S. patents: U.S. Pat. No. 4,632,100--Somers et al.; U.S. Pat. No. 4,899,743--Nicholson et al.; U.S. Pat. No. 4,946,468--Li; U.S. Pat. No. 4,968,315--Gatturna; U.S. Pat. No. 5,002,550--Li; U.S. Pat. No. 5,156,616--Meadows et al.; U.S. Pat. No. 5,207,679--Li; and U.S. Pat. No. 5,217,486--Rice et al.
The prior art suture anchors, exemplified by the above-noted patents, require the suture to be threaded through the anchor before the anchor is installed in the bone mass. In some cases, however, installing an anchor that is pre-threaded with a suture may present some problems. For example, in using suture anchors of the self-tapping, threaded shank type (see, e.g., U.S. Pat. No. 4,632,100--Somers at al. and U.S. Pat. No. 5,156,616--Meadows et al., supra) that require a twisting motion for installation, the suture may be prone to being twisted during installation. This is especially a problem when it is necessary to thread a suture through two anchors, since, with both anchors pre-threaded with the suture, twisting of the suture during installation of the second anchor is virtually inevitable. Furthermore, care must be taken, during installation of a self-tapping anchor that is pre-threaded with a suture, to avoid abrasion of the suture by the anchor driving tool.
Thus, there are often times when it would be advantageous, or even necessary, to thread the suture through the suture anchor after the anchor has been installed. This, however, may be difficult to do in practice, due to the thinness and limpness of the suture, the small size of the anchor eyelet through which the suture must be threaded, and the confined space at the surgical site for manipulation of the suture (especially in percutaneous procedures).
Accordingly, there has been a long felt need for a method and associated apparatus for threading a suture through a suture anchor in situ after the anchor has been installed. It would be of additional advantage if such a method and apparatus would be economical to manufacture and simple to use.